Chain grate



W. M. DUNCAN.

CHAIN GRATE.

APPLICATION mw Nov. 23. 911. nfuzwso Juni 2r. |920.

Patented Jan. 18, 1921.

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tit-tiren strates WILLIAM M. DUNCAN, OF ALTON, ILLINOIS.

CHAIN GRATE.

Application led November 23, 1917` Serial No. 203.533.

To all whom lz5 may colmi/12:

Be it known that I, IVILLIAM M. DUNGAN, a citizen of the United States of America, a resident of Alton, in the county of Madison, State of Illinois, have invented certain new and useful Improvements in Chain Grates, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing. forming' a part of this specification.

My invention relates to improvements in chain grates, the main object being to produce a grate of this kind having its links so constructed that the draft between the chains will flow transverselyv of the fuel supporting elements, instead of being permitted to flow longitudinally of the grate structure. Prior to this invention, chain gratos have been made of endless rows of grate links, loosely connected together' to permit the draft to pass through the grate structure. The object is to force the draft transversely of the chains, to or from the fuel supported thereon. However, in the learlier stint-tures, the air currents between the loosely connected grate links can flow longitudinally of the grate, and escape through a course of low resistance, instead of passing through the bed of fuel at points where the draft is needed. In some chain grate structures it is desirable to provide a strong draft near the point at. which fuel is delivered to the grate, and to weaken or dispense with the draft near the rear end of the structure where the ashes are discharged from the grate. I have manufactured many chain grates having different draft Zones and provided with independent damper-s for the purpose of regulating the draft at the different Zones. Theoretically, this is most desirable, but in actual practice the highest eliiciency cannot be obtained if the draft is permitted to pass longitudinally ot' the grate, from one zone to another.

According to the present invention, the grate links are provided with baliles for obstructing the air currents tending to flow longitudinally of the grate structure. The baffle extending from a. side of a grate link, preferablyv lies between the ends of two links in an adjacent row, so as to prevent the air currents from Howing longitudinally of the rows of links.

Figure I is a longitudinal section of a Specification of Letters Patent.

Patented Jan. 18, 1921.

Renewed June 21. 1920. Serial N0. 390,668.

chain grate constructed in accordance with the present invention.

Fig. II is an enlarged fragmentary plan view, showing a number of grate links and the pivot rods connecting said links, the end portions of two linksy being broken away to show one` of the baffle members which lies directly below said end portions.

Fig. III is a side elevation of the parts shown in Fig. II.

Fig. IV is a transverse section taken approximately on the line IV-IV, Fig. III.

Fig. Y is a perspective view of one of the grate links.

To illustrate the invention I have shown a supporting frame l provided with a hopper 2 for the discharge of fuel to a chain grate A. rl`he grate structure comprises many endless rows of `frate links A', and pivot rods 3 connecting said grate links. The endless chains produced by `connecting the grate links` are fitted to toothed drive wheels *i fixed to a power :haft 5 near one end of the supporting frame, and also fitted to idle wheels (S near the opposite end of said frame. T he links at the upper portion of the grate structure travel over rollers 7. while the lower links travel over rollers 8. The power shaft 5 may be operated in any suitable manner.

9 designates draft boxes, surrounded bv the endless chains` said draft boxes being open at the top for the discharge of air to the fuel supporting elements. Some of the rollers 'T are combined with flanged members l0 or l0 to form ash-seals at the upper edges oi' the draft boxes. The ashes aecuniulating between rollers 7 and the flanged members l0 or l0` prevent the draft fir-fr etarras bewffan flic upper edges of the draft boxes 9 and the bottom facer: of the adjacent grate links. Dampers l2, arranged in the draft boxes 9, can be regulated indepenvantly of each other to control the draft at different points in the lbed of fuel. A relatively sti-oner draft sl'iould-usually be maintained near the front end of the structure where the fuel is delivered to the grate, but the dra ft can usually be entirely dispensed with near the rear end of the grate, where the ashes are discharged therefrom. To obtain the highest eliieiency, the dampers l2 can be adjusted to control the draft at various` different points in the grate structure. Obviously, the desired results could not be obtained if the air currents between the rows of links are permitted to flow longitudinally of said rows of links. The air passing from the top of the draft box should iiw vertically between the rows of links, and to accomplish this it is necessary to prevent the air from flowing longitudinally of the links.

In the preferred form of the invention, the grate links A areprovided with baffles B in the form of ribs, as shown most clearly in Fig. V. Each grate link is also provided, near its ends, with pivot receiving openings 3 (Fig. V) and the baiiie rib B is formed on one side of the link, approximately midway between said openings. It is important to observe that the links of the adjacent chains are staggered relative to each other, so that the ends of any given link are not in alinement with the ends of the links on opposite sides thereof. The baffle rib B, extending from one of the interposed links, lies between end portions of two links of the next adjacent chain. The upper end portions of each link are extended as shown at 13 (Figs. III and V) and 'these extended end portions lie directly above a baffle rib B. In other words, the baffle ribs of one chain overlap and lic between the ends of the links of an adjacent chain. In the struc ture shown, the baffle ribs B are approximately as wide as the link from which they extend, and each baffle rib therefore extends across the links which it overlaps, as shown most clearly in Figs. II and IV.

By forming the links with baiile ribs B as herein disclosed, I provide a multitude of baffles, each extending from one link and overlapping lthe ends of adjacent links, so as to very effectively impede the air currents tending to How longitudinally of the grate, As a result, the draft can be directed to any particular point on the bed of fuel, and the air currents are prevented from taking a course of low resistance by flowing through the thin bed of ashes near the rear end of the grate.

In moving around the wheels l and 6, the grate links turn on their pivots 3, and clinkers, or the like, will sometimes drop between the separated ends of the links passing around the wheels 6. Thereafter, when the separated ends move toward each other, the clinkers, or the like, will be crushed at the upper ends of the baffle ribs B. The upper end of each baille rib is enlarged, and the top face of this enlarged portion is recessedy to form a pocket 111 for the crushed material resulting from the crushing of clinkers or the like.

I claim 1. A chain grate comprising rows of grate links, the links of one row being provided withy baffles which overlap the links of the vided with baiiles which overlap the links J.

of the next adjacent row to impede the air currents tending to flow longitudinally of the grate, said baffles being in the form of ribs extending laterally from the sides of the grate links at their lower portions when the links are in fuel-supporting positions.

3. A chain grate comprising rows of grate links, the links of one row being provided with baffles leading into proximity to the lower edges of the links and which extend between the links of the next vvadjacent row.

4. A chain grate comprising endless rows of grate links, the links of adjacent rows being staggered relative to each other, so that the ends of the links in an interposed row are not in alinement with the links at opposite sides thereof, said' interposed links being provided with baffles which extend between the ends of the links'in an adjacent row, so as to impede the air currents tending to iiow longitudinally of the grate, each of said baffles comprising a rib4 formed on one side of a grate link and extending from near the lower edge of the link to a point near the top of said link.

5. A chain grate comprising end-less rows of grate links, the links of adjacent rows being staggered relative to each other, so that the ends of the links in an interposed row are not in alinement with the links at opposite sides thereof, said interposed links being provided with baffle ribs which extend between end portions of the links in an adjacent row, soy as to impede the air currents tending to ow lon itudinally of the grate, and the upper en portions of the links being extended so as to overlie said baffle ribs.

6. A chain grate comprising endless rows of grate links, the links of adjacent rows being staggered relative to each other, so that the ends of the links in an interposed row are not in alinement with thelinks: at opposite sides thereof, draft boxes surrounded by said endless rows of grate links, said draft boxes being open at the top for the discharge of air currents transversely of the upper portion of the grate, and means for controlling the flow of air through said draft boxes so as to control the draft at different parts of the grate, said interposed links being provided with bafHes which extend between the end of the links in an adjacent row and into proximity to the lower edges of the links, so as to impede the air currents tending to flow longitudinally of the grate. t

7. A grate link having pivot receiving openings near its ends, and a bailie approximately midway between said openings, said baille being in the form of a rib extending laterally from one side of the link and into proximlty to the lower edge of the link.

8. A grate link of the character described having pivot receiving openings near its ends, and a baffle rib extending from the lower edge of the link to a point near the upper edge thereof, said baille rib being formed on one side of the grate link approximately midway between said openings, and the upper end portions of the link be ing extended for the purpose described.

9. A grate link of the character described having pivot receiving openings near its ends, and a baille rib extending from the lower edge of the link to a point near the upper edge thereof, the top face of said baffle rib being recessed to form a pocket, said baille rib being formed on one side of the grate link approximatel midway between said openings, and t e up er end portions of the link being extend for tht` purpose described.

In testimony that I claim the foregoing I hereunto alix my signature.

WILLIAM M. DUNCAN. 

